This invention relates generally to radar systems and more particularly to active radar transmitting systems. More specifically, for example, the invention relates to a detector for detecting faulty radar transmitting tubes of high-power radar transmitting systems.
In the past, the U.S. Navy has employed expensive diagnostic equipment to assess whether certain high-power, pulsing type, microwave radar transmitting systems are working as intended. Such techniques employed, for example, expensive digitizing oscilloscopes and spectrum analyzers each costing over $25,000. Use of such equipment can be cumbersome and taxing at inopportune times.
There is a need for a low-cost test device that can be built into radar systems wherein testing can be performed on an active system in real-time with minimal complexity and cost.
The invention is designed to test whether a radar, pulse type, transmitting tube is faulty or not. This assessment is based upon an observation that faulty radar pulses have a significantly increased content of undesired high frequency components in their cathode current sensed at the cathode lead of an operating radar transmitting tube.
The invention exploits this observation by sensing the current at the transmitting tube""s cathode and by high pass filtering only those frequency components known to be indicative of faulty transmitting tubes.
The filter output is fed to a detector that converts the analog output of the filter into a rectified output that is proportional to the amplitude of the high frequency voltage components passing through the filter. The high-pass output is smoothed and the smoothed output is fed to an analog-input, digital output threshold amplifier. The threshold amplifier provides a TTL output that corresponds to a smoothed amplitude that is considered to represent a good radar pulse or to a smoothed amplitude value representing a faulty pulse. The TTL logic output then is input to a digital data processor which uses predetermined algorithms to assess the condition of the transmitting tube based upon the rate of occurrence of the bad radar pulses. The output of the processor is then sent to a data collection and storage system whose files are available for observation by a radar system operator.
An object of this invention is to provide a device for testing radar systems.
Another object of this invention is provide a device for testing radar systems that is relatively simple and inexpensive.
Still another object of the invention is to provide a built-in device for testing radar systems.
A further object of the invention is to provide a device that tests the transmitting tube of a radar system.
Still yet another object of this invention is to provide a device that tests the transmitting tube of a radar system by exploiting a characteristic of faulty radar pulses.
Still a further object of this invention is to provide a device that tests the transmitting tube of a radar system by assessing the current characteristics as provided at the cathode of the tube.
Other objects, advantages and new features of the invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanied drawing.